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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The clinical course of MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes) is described in five cases. The age of onset was 9.2 years on average. Cerebral symptoms occurred at an age of 24.6 years on average. The diagnosis was only made later. Three patients died during the follow-up period. The mean age at death was 33.3 years, the average duration of the disease, 19.6 years. All patients suffered from progressive hearing loss, multiple strokes, and complex-partial and generalized seizures. They all had short stature, normal early development and 'ragged red fibers' in the muscle biopsy. Imaging studies (CT and MRI) showed bilateral calcification of basal ganglia and multiple strokes. One patient, admitted with epileptic status as initial symptom, showed lymphocytic pleocytosis in the cerebrospinal fluid; thus, in her case the differential diagnosis included encephalitis. Four patients were studied by dynamic endocrinological testing. Endocrinological disturbances were detected in three patients. Two of them suffered from hypothalamic-pituitary failure and one patient exhibited hyperprolactinemia. Endocrinological disturbances were considered an expression of the underlying cytopathy. Cerebral symptoms occurred rather late in the course of the disease and indicated poor prognosis.
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PMID:[Follow-up studies and disorders of endocrinologic function in MELAS syndrome]. 876 1

A number of human diseases are caused by inherited mitochondrial DNA mutations. Two of these diseases, MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) and MERRF (myoclonic epilepsy and ragged-red fibres), are commonly caused by point mutations to tRNA genes encoded by mitochondrial DNA. Here we report on how these mutations affect mitochondrial function in primary fibroblast cultures established from a MELAS patient containing an A to G mutation at nucleotide 3243 in the tRNA(Leu(UUR) gene and a MERRF patient containing an A to G mutation at nucleotide 8344 in the tRNA(Lys) gene. Both mitochondrial membrane potential and respiration rate were significantly decreased in digitonin-permeabilized MELAS and MERRF fibroblasts respiring on glutamate/malate. A similar decrease in mitochondrial membrane potential was found in intact MELAS and MERRF fibroblasts. The mitochondrial content of these cells, estimated by stereological analysis of electron micrographs and from measurement of mitochondrial marker enzymes, was similar in control, MELAS and MERRF cells. Therefore, in cultured fibroblasts, mutation of mitochondrial tRNA genes leads to assembly of bioenergetically incompetent mitochondria, not to an alteration in their amount. However, the cell volume occupied by secondary lysosomes and residual bodies in the MELAS and MERRF cells was greater than in control cells, suggesting increased mitochondrial degradation in these cells. In addition, fibroblasts containing mitochondrial DNA mutations were 3-4-fold larger than control fibroblasts. The implications of these findings for the pathology of mitochondrial diseases are discussed.
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PMID:Altered mitochondrial function in fibroblasts containing MELAS or MERRF mitochondrial DNA mutations. 880 26

A mitochondrial A 3243 G mutation in the tRNA(Leu(UUR)) gene was first described as a common cause of MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like syndrome). This same mutation is also the cause of a totally different disorder, a subtype of diabetes mellitus which is inherited maternally and often associated with sensorineural hearing loss. In this paper, we report on a Japanese boy with A 3243 G who developed a previously undescribed combination of symptoms, nephropathy and growth hormone deficiency. The patient first presented with short stature and moderate mental retardation. Growth hormone (GH) provocation tests showed deficient growth hormone secretion. During the course of follow up, he presented with progressive nephropathy followed by the development of diabetes mellitus. The results of laboratory tests and renal biopsy were against incidental association of known types of nephropathy. On PCR-RFLP analysis, the percentage of mutated mtDNA was higher in the renal biopsy specimen than 12 peripheral blood leucocytes. Our case suggests that mitochondrial diseases should be taken into account when there is nephropathy of unknown cause. In addition, the presence of growth hormone deficiency may account for part of the mechanism leading to short stature commonly seen in these patients.
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PMID:Nephropathy and growth hormone deficiency in a patient with mitochondrial tRNA(Leu(UUR)) mutation. 881 55

We studied the prevalence of mitochondrial gene mutations in subjects with insulin-dependent diabetes mellitus (IDDM) in a Chinese population living in Taiwan. Eighty-four subjects with insulin-dependent diabetes mellitus and 105 unrelated normal controls were recruited in the present study. Both an A-to-G mutation at position 3243 and a mutation at position 8,344 of the mitochondrial DNA were screened by polymerase chain reaction-restriction fragment length polymorphism methods and confirmed by direct DNA sequence analysis. The insulin secretory response was assessed by the C-peptide response to glucagon administration. Among 84 IDDM patients, two (2.4%) subjects were found to carry the 3,243 nucleotide pair (np) mutation. There was no np 8,344 mutation in this series. Of the two subjects carrying a mitochondrial gene mutation, case 1 manifested initially as gestational diabetes mellitus. Manifestation of case 2 was consistent with MELAS, a syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. The pancreatic beta cell reserve was reduced, as the glucagon-stimulated C-peptide response was very low in these two cases. HLA genotyping studies revealed that case 2 carried DRB1*0301-DQA1*0501-DQB*0201/ DRB1*0405-DQA1*0301-DQB1*0302, which was the most susceptible genotype to IDDM in our population. Anti-GAD65 antibody was also positive in this patient. In addition to the nuclear genes, a defective mitochondrial gene might contribute to some of the clinical cases with IDDM.
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PMID:Mitochondrial gene mutations in patients with insulin-dependent diabetes mellitus in Taiwan. 883 Mar 30

We describe a family with two cases of adult-onset mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome. Interestingly, the proband also had non-insulin dependent diabetes mellitus and hyperthyroidism. Endocrinological studies demonstrated a high titer of TSH receptor antibody in the proband and elevated levels in her maternal relatives. Analysis of mitochondrial DNA (mtDNA) showed an A-to-G transition at nucleotide position 3243 in the tRNA (Leu(UUR)) gene (A3243G) in the three generations of the family. Furthermore, a previously described -260 bp tandem duplication in the D-loop region of mtDNA was also found in the proband and her maternal relatives. To our knowledge, such kind of duplication has never before been reported in the MELAS syndrome. The proportions of mtDNA with the -260 bp tandem duplication and A3243G point mutation were 12.5% and 82% in the muscle, respectively, and 1.6% and 35% in the blood cells, respectively, of the proband. We conclude that the hyperthyroidism in this MELAS patient may be related to the tandem duplication in the D-loop of mtDNA. This study further substantiates the importance of searching for additional genetic mutations in mitochondrial encephalomyopathic patients with new clinical phenotypes.
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PMID:MELAS syndrome associated with a tandem duplication in the D-loop of mitochondrial DNA. 883 8

Typical cases of MELAS present a combination of clinical and neuroradiological features, lactacidaemia, and ragged red fibers (RRFs) in striated muscle. We have observed a MELAS-like syndrome in monozygotic twins. They developed seizures typically in conjunction with physical exertion, sleep deprivation or febrile episodes. Stroke-like episodes occurred usually during seizures. In twin 2 the course was fatal at age 20 years. Neuroradiological findings were typical of MELAS. Plasma lactate was normal in both. CSF lactate was normal in twin 1 and normal/elevated in twin 2. RRFs were not seen in muscle biopsies of the twins. Complex I activity was reduced in muscle in twin 1. Brain tissue removed at epilepsy surgery in twin 2 showed the presence of mitochondrial angiopathy. The commonest mitochondrial DNA mutation in MELAS, at base pair 3243, was absent. Lactacidaemia and mitochondrial myopathy with RRFs constitute part of the diagnostic criteria of MELAS. However, the absence of these features does not exclude mitochondrial disorder with the serious manifestations of MELAS (seizures and stroke-like episodes) as seen in these twins.
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PMID:Monozygotic twins with MELAS-like syndrome lacking ragged red fibers and lactacidaemia. 893 33

Various mutations in the mitochondrial tRNA(Leu)(UUR) gene give rise to a variety of neurological disorders. Among these, mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS syndrome) are frequently associated with a tRNA(Leu)(UUR) mutation at nucleotide position 3243 of the mitochondrial DNA. A supplementary clinical feature seen in these patients is headache in early life. Recently, a tRNA(Leu)(UUR) mutation at nucleotide position 3243 has been found in a patient presenting with cluster headache. This led us to examine the mitochondrial genomes of 22 patients presenting with cluster headache. None of the patients harboured the reported tRNA(Leu)(UUR) mutation or any other length variations of the mtDNA. Cluster headache is most likely not causally associated with the A3243G mutation of the mitochondrial DNA.
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PMID:Investigation on the mitochondrial transfer RNA(Leu)(UUR) in blood cells from patients with cluster headache. 896 1

The expression of several mitochondrial and nuclear genes involved in ATP production was examined in cells cultured from muscle biopsies of patients harboring mitochondrial pathologies. The transcript patterns in muscle cells from the patients affected by carnitine palmitoyl transferase II or 2-ketoglutarate dehydrogenase deficiencies were almost similar to control patterns. In the opposite, patterns were strikingly abnormal in all the other cell cultures from patients with defects in enzymatic complexes involved in oxidative phosphorylation: mitochondrial complex II and III deficiencies, two MELAS syndromes (myopathy, encephalopathy, lactic acidosis and stroke like episodes), a case of Kearns-Sayre syndrome and a case of chronic progressive external ophthalmoplegia. In cultured muscle cells from patients with mtDNA mutations, the percentage of mutated mtDNA was low as compared with those determined in the corresponding skeletal muscle biopsy. Moreover, the complex II defect resulting of a nuclear mutation was not expressed in the cell cultures. Thus, an undetermined transcriptional event, transmitted from muscle biopsies to cultured muscle cells, should be involved to account for such abnormal transcript patterns.
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PMID:Expression of oxidative phosphorylation genes in muscle cell cultures from patients with mitochondrial myopathies. 906 96

We report a 47-year-old female patient showing clinical features of chronic progressive external ophthalmoplegia (CPEO) without stroke-like episodes. Large scale deletion of mitochondrial DNA (mtDNA) was not found in her biopsied muscle, whereas the A-->G transition at position 3243 (A3243G) was detected. The patient's mother had diabetes mellitus, suggesting maternal inheritance. This mutation is usually associated with MELAS, but wide clinical variety of the mutation has been recognized. Although several patients of CPEO with A3243G mutation (CPEO3243) have been found in the Western countries, only one case has been reported in detail in Japan. The CPEO3243 patients, including ours, show retinopathy less frequently, but diabetes mellitus and hearing loss more frequently than CPEO patients with deletions of mtDNA (CPEO delta). CPEO3243 is usually inherited maternally, but almost all CPEO delta is sporadic. With regard to COX activity of biopsied muscles, CPEO3243 resembles CPEO delta more than MELAS3243. This suggests that how the mutant mtDNA is distributed among cells or tissues may have more significant effect on clinical phenotype than what type of mtDNA mutation exists. The presence of such a CPEO3243 patient like ours could be an important suggestion toward further understanding of mitochondrial diseases.
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PMID:[A case of mitochondrial encephalomyopathy showing ophthalmoplegia, diabetes mellitus and hearing loss associated with the A3243G mutation of mitochondrial DNA]. 924 43

We report the clinical, pathological, and genetic findings of a case of MELAS syndrome. This was a man who died for metabolic failure at the age of 27 years. His familiar history was positive for hypoacusia and stroke. He was of short stature and presented mild mental retardation. Since the age of 21 he suffered from recurrent brain-ischemic lesions mainly in the occipital lobes, documented by repeated CT scans. The laboratory data and muscle biopsy disclosed lactic acidosis with ragged red fibres. Neurophysiological data and peripheral nerve biopsy showed an axonal neuropathy. A point mutation in the tRNALeu(UUR) gene of mitochondrial DNA was detected in 5 post-mortem tissues and in muscle biopsy. No defects of mitochondrial respiratory chain were detected. The histological and ultrastructural studies of the brain showed multiple and heterogeneous ischemic lesions with no obvious alterations of cerebral blood vessels. These lesions do not correspond to the vascular territories of main cerebral arteries. Our observations support the hypothesis that local metabolic alterations would play a crucial role in the pathogenesis of cerebral ischemic lesions in MELAS. The correlation between genetic, biochemical, and pathological data are discussed.
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PMID:Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). 926 44


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